Knee torsion predicts the preoperative J-sign grade in patients with recurrent patellar dislocation
A threshold of 5° to 6° of torsion in the knee is associated with patellar maltracking in extension. In patients with recurrent dislocation of the patella, there is a one-grade increase in J-sign for approximately every 4° increase in torsion. The 7° and 12° of torsion represent the thresholds for the preoperative J-sign -/1+, J-sign 2+, and J sign 3+, respectively. Routine bilateral lower limb CT scans are therefore required if surgery is to be considered in the knees of patients with recurrent dislocation of the patella who have a positive J-sign.
Authors
- Yanwei Cao (ORCID: https://orcid.org/0000-0002-9759-7346)
- Tong Zheng (ORCID: https://orcid.org/0000-0002-2666-7618)
- Daofeng Wang (ORCID: https://orcid.org/0000-0002-0743-4325)
- Hui Zhang (ORCID: https://orcid.org/0000-0001-7434-7806)
- Zhijun Zhang (ORCID: https://orcid.org/0000-0002-6859-3426)
- Xuesong Wang (ORCID: https://orcid.org/0000-0002-3686-333X)
Institutions
- Capital Medical University (CN)
- Peking University (CN)
- Beijing Jishuitan Hospital (CN)
- Beijing Institute of Neurosurgery (CN)
Publication Details
- Journal
- The Bone & Joint Journal
- Published
- 2025-05-01
- DOI
- https://doi.org/10.1302/0301-620x.107b5.bjj-2024-0766.r2
- Primary Topic
- Lower Extremity Biomechanics and Pathologies
- Type
- article
- Field-Weighted Citation Impact
- 0.00